1. Field of the Invention
The invention relates to information storage devices and more particularly to a monolithic device for the sequential charge transfer of a signal which is tapped and filtered in accordance with a predetermined function.
2. Description of the Prior Art
Monolithic transversal filters utilizing charge transfer circuits have developed rapidly in recent years. From the outset, it was apparent that the tapped outputs along the delay line had to be weighted on the chip itself, since individual lead outs for the various taps consumed a substantial amount of space. Various methods for on-chip weighting have been developed such as the split electrode technique, the weighted capacitor technique, the weighted transconductance technique, etc. as described by Puckette et al, in an article entitled "Bucket Brigade Transversal Filters", IEEE Transactions on Communications, Vol. COM-22, No. 7, July 1974, pages 926-934, inclusive. As indicated in that article, all of these methods require that the positive weights and negative weights be grouped separately and differentially summed to give the appropriate output.
The present invention, then is a monolithic transversal filter which incorporates all of the necessary functions, including differential summing, in a minimal amount of chip space, and which in addition thereto, can be economically fabricated.